The mangled content in your image is essentially a newsfeed, so something is intercepting dataflow and altering it. It's possible to clean out hacks, but if you miss one thing, it could reappear and you have to start the process all over again.

You're really better off doing a complete, clean reinstall. Delete everything from the server and database. Reinstall a clean wordpress and restore database and uploads etc. from a known clean backup.

Well, perhaps not, but to be absolutely sure you've removed all traces of the hack, you should. Some hacks back themselves up in multiple locations. So unless you wipe everything at once and start over, the hack could save itself in another area while you clean one area. Then when you move on to the next area to clean, the hack restores itself to the area you just cleaned.

So unless you wipe everything at once, you could end up running in circles trying to clean out the hack.